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IDAPython is a way to script different actions in the IDA Pro disassembler with Python. This repository of scripts automates many different processes necessary when analyzing the firmware running on microcontroller and microprocessor CPUs. The scripts are written to be easily modified to run on a variety of architectures. Read the instructions in the header of each script to determine what ought to be modified for each architecture.How to Run

data_offset_calc.py -- Resolve Indirect Offset Memory Accesses Resolves the references to indirect offsets of a variable, register, or memory location whose value is known. Changes the display of the operand in the instruction (OpAlt function), creates a data cross references (add_dref), and creates a comment of the resolved address (MakeComment). User nees to define the following: offset_var_string: The string representation of the variable, register, or memory location to be replaced by the resolved value offset_var_value: The value of the variable defined in offset_var_string reg_ex_indirect: A regular expression of how indirect offset accesses to the variable reg_ex_immediate: A regular expression of how the immediate offset value is represented new_opnd_display: A string representation of how the calculated and resolved value should be displayed as the operand in the instruction

define_code_functions.py -- Define Code and Functions This script scans an area of the database from the user input "start address" to "end address" defining the bytes as code and attempting to define functions from that code. The script is architecture agnostic by having the user define a regular expression for the "function prologue" and the "function epilogue" for the architecture being analyzed.

define_data_as_types.py -- Define a Block as Data Defines a segment of addresses as the user-specified data type (byte, word, or double word). The byte length for each of these types is architecture dependent, but generally: 1 byte = Byte 2 bytes = Word 4 bytes = Double Word This script with undefine all bytes in the range first which means if you previously had code or strings defined in the area, they will be overwritten as data.

make_strings.py -- Define a Block as Strings This script is used to search for and declare blocks of "Unexplored" bytes as ASCII strings. The user inserts the starting and ending address of the areas to be analyzed. The script then checks if each byte is an ASCII character value and ends with a defined "ending string character." In this example, the ending string characters are 0xD, 0xA, and 0x00. The script only checks "undefined or unexplored" values in the database. For example, if a string is currently defined as code, it will not identify this string. This is to protect previously defined values.

label_funcs_with_no_xrefs.py -- Label All Functions without Cross-References/ Valid Code Paths This script identifies what could be "dead code". It checks each function for cross-references to the function in question. If there are none, it adds the prefix "noXrefs_" to the function name. This is very efficient for architectures that do not call functions indirectly.

identify_port_use_locations.py -- Find All CPU Port Usage Identifies all code using the CPU's ports and records the address and instruction in the identified file. There is the option to annotate each function that accesses a CPU port/pin with a prefix stating that it's using the specific port/pin.

find_mem_acceses.py -- Identify Memory Accesses Identifies the memory accesses used in the code. When a memory access is identified based on the user contributed regular expression, this script completes three different actions to help with the static analysis:

A cross reference is created between the instruction and the memory address. This will fail if the address doesn't currently exist because the segment was not created.

The value at the memory address is retrieved and added as a comment to the referencing instruction.

A dictionary of all of the memory addresses accessed and the referencing instructions' addresses are printed and saved to a file.

identify_operand_locations.py -- Identify Instructions that Reference an Operand Identifies the instructions in the range start_addr to end_addr that reference the input operand (regex_operand). The addresses of all instructions where the operand is found are printed to the IDA output window and saved to a file.

Copyright

Copyright 2017 The Johns Hopkins University Applied Physics Laboratory LLC All rights reserved. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so.
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